This behavior is documented but isn't obvious or desired in many cases -
Placement type - specify the Compute resource selection algorithm, that will be used on virtual server provisioning and recovery, per Compute zone:
Take HV with maximum free RAM (Sparse) - set this type to select the Compute resource with maximum free RAM during the VS recovery. This option allows performing faster migration of virtual servers with the lesser (sparse) number of iterations during the failover.
This option behaves in different ways, depending on the event:
- On provisioning, the round-robin algorithm will be used on Compute resource selection.
On recovery, the Compute resource with maximum free RAM will be selected.
The placement on creation should likely be a separate option, possibly with considerations for # of VM already on the HVs, how much CPU is assigned to the HVs, HV actual load, possibly network traffic, to determine good place to put VM.
Round Robin placement hiding behind "Take HV with maximum free RAM (Sparse)" option is odd, and with KVM HVs can cause issues starting new VM under some circumstances of high cache/buffers taking memory on the HV
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